Three member microscope objective having a magnification of 20x

ABSTRACT

A THREE MEMBER MICROSCOPE OBJECTIVE HAVING A NUMERCAL APERTURE OF SUBSTANTIALLY 0.50 AND A MAGNIFICATION OF SUBSTANTIALLY 20X.

SR TV/EZa/f Jan. 5, 1971 A. H. SHOEMAKER THREE MEMBER MICROSCOPEOBJECTIVE HAVING A MAGNIFICATION 0F 20X Filed Dec. 9, 1968 INVENTOR.

IIRTHUR H. SHOEMAKER M. as

ATTORNEY United States Patent 3,552,830 THREE MEMBER MICROSCOPEOBJECTIVE HAVING A MAGNIFICATION 0F 20X Arthur H. Shoemaker, EastAurora, N.Y., assignor to American Optical Corporation, Southbridge,Mass., a

Description Referring now to the drawing, a microscope objective isgenerally shown at 2. It includes a front single lens corpomfion ofDelaware 5 t, a doublet 6, and a doublet 8, all of said lensesbeing Fi pg, 19 33 .31 732,05 in axial alignment. ObjBCtlVB 2 is disposed relativeto Int. Cl. G02b 9/12, 21/02 an object plane as shown in the drawing.U.S. Cl. 350-176 2 Claims I Lens 4, also designated I, is a singleconcavo-convex 10 lens. Doublet 6 includes a convex-concave lens II anda a double convex lens III, together forming a double con- ABSHMCT THE gj i vex doublet. Doublet 8 includes a convex-concavo lens A three membermlcfoscqpe Objective havmg IV and a double convex lens V, togetherforming a doumerical aperture of substantially 0.50 and a magnificableconvex doublet non of substamlany The lens parameters are as follows:The successive lens radii are designated Rl-RB, where a minus signBACKGROUND OF THE INVENTION ndicates radii on centers of curvature lyingon the obect side of their vertices. The axial thicknesses of suc-Present mvemlon relates to a mlcroscope cessive lens elements aredesignated t1-t5. The succesectrve. sive axial spaces from the objectplane 14 are designated flan ob ect of the prezent unvgntron 15 toprovllde an 81-83. The refractive indices of the successive lens elerggg g ggggzig d l a: ggg i glfigfi g gfg: ments are designated NDl-NDS.The Abbe numbers of stantially 20X, in which chromatic and sphericalaberthe i f lens glasses are designated 'YIM/s rations, coma, andastigmatism are well corrected while Spec we yet providing asubstantially flat image field, when used The above-mentlqned Paramaersrelated Q the with a telescope objective as described in US. Pat. No.focal length acwrdmg to the followmg n tr tional 3,355,234. data:

[Magnification-20X; N.A.=0.60]

' Refractive Abbe Lens Radius, R Thlckness,t Space, S Index, ND Number,

S1-=.1849F I Rl=-.4306F ll=.|5346F ND1=L78833 71=60.47 R2=.6060FS2=.0286F R3=2.8566F II l2=.3216F ND2-L80489 72=25A5 R4=1.0188F IIIt3=.6530F ND3==L69669 3=55.60

R5=-l.3928F S3=.7479F R6=26.2749F Iv t4=.1994F ND4=1.80785 4=40.72

R7=L2375F v t5=.6212F ND6=1.50371 5=66.72

DRAWING The foregoing parameters of radius, thickness and space arebased on the value of F. The value of F in this In the drawmg, a mOblectlve represented case, as an example, is 9.1385. Given in numbers,the by a plurality of lenses viewed transversely to their axis.foregoing data is as follows:

[F=9.1385; Magnification=20X; N.A.=0.50]

Refractive Abbe Lens Radius,R Thlckness, Space, S Index, ND Number,

S1==1.690 Rl=-3.935 I z1=4.ss5 ND1=1.78833 1=50.47

S2=.260 R3=26.105 II z2=2.939 ND2=1.80489 2=25.4u

R4=9.310 III t3=5.967 ND3=L69669 73=55.60

.sa=a.sa5 R6=240J13 Iv z4=1.s22 ND4=1.80786 -,4=4o.72

R7=1L309 v t5=5.677 ND5=1.50271 5:66.72

3 It will be apparent that the foregoing absolute values are variabledepending on the value of F. Other forms are thus possible and changesmay be made in the values of the constructional data based on therelationships in (tl-t), axial Spaces among lens elements and objectplane (S143), refractive indices (NDl-NDS), and Abbe numbers (ml-v5),being determined by the following relationship:

the first of the above charts, without departing from the spirit of thisinvention.

What is claimed is:

1. An achromatic microscope objective having a magnification ofsubstantially X and a numerical aperture of substantially 0.50 forforming an image of an object plane, said image being well corrected forspherical and chromatic aberrations, coma, astigmatism and whereinscalar values are given in millimeters.

2. An achromatic microscope objective having a magnification ofsubstantially 20X and a numercial aperture of substantially 0.50 forforming an image of an object plane, said image being well corrected forspherical and chromatic aberrations, coma, astigmatism and curvature ofimage field, said objective comprising:

a front concavo-convex lens member I;

curvature of image field, said objective comprising: iffg gi)anvcexconclaylo lens brleiililber II;

a front concavo-convex singlet lens member I; a r u e o f' e Smem r condconvex concavo lens member said second and third members forming adoublet; a d d bl l b a fourth convex-concavo lens member IV; i 21? em ger d bl afifth double convex lens memberV; 531d second ormmg a saidfourth and fifth members forming a doublet; a fourth convexconcavo lensmember all of said lens members being axially aligned; and a fifthdouble CO I BX lens member the parameters of lens radii (R1R8), lensthick- Said f r a fifth members fofmmg a doublet; nesses (ll-t5), axialspaces among lens elements all of said lens members being axiallyaligned; and and object plane (Sl-SJ), refractive indices (ND1- theparameters of lens radii (RI-R8), lens thicknesses NDS), and Abbenumbers (71- 5), as follows:

Refractive Abbe Lens Radius, R Thickness! Space, S Index, ND Number,

s1==1.690 R1=3.935 1 n=4.ss5 ND1=1.78833 1=50.47

S2=.260 R3=26.105 II z2=2.939 ND2=L80489 2:25.45

R4=a310 111 t3=5.967 ND3=L69669 3=55.60

S3=6.835 R6=240.113 1v z4=1.822 ND4=L80785 4:10.72

R7=1l.309 v t5=5.677 ND5=L60271 5=sa72 wherein scalar values are givenin millimeters.

References Cited UNITED STATES PATENTS 3,437,398 4/1969 Muller et al.350225X JOHN K. CORBIN, Primary Examiner US, Cl. X.R

